JP 3487744 (Patent Document 1) discloses that a cured gel product having well balanced heat resistance, chemical resistance, solvent resistance, water repellency, oil repellency, weatherability, and the like can be produced by curing a composition containing a straight chain perfluoropolyether compound having at least two alkenyl groups per molecule and including a perfluoropolyether structure in its backbone; a straight chain perfluoropolyether compound having one alkenyl group per molecule and including a perfluoropolyether structure in its backbone; an organosilicon compound having at least two hydrosilyl groups per molecule; and a hydrosilylation catalyst.
Such perfluoropolyether gel composition has sufficient performance for almost all applications. However, higher acid resistance may be required in the applications where chemical resistance is required, for example, in the applications such as a sealant for semiconductor production system, a sealant and potting agent for engine oils, and a sealant and potting agent for engine exhaust parts. Accordingly, there is a strong demand for a perfluoropolyether gel composition having excellent oil resistance and chemical resistance, and in particular, an excellent acid resistance.
Prior art documents relevant with the present invention include those as described below.
Of these, the polymer having an [aromatic ring—Si atom—vinyl group] structure at its terminal described in Japanese Patent 2990646 is known to have an excellent rapid curability due to the presence of the [Si atom—vinyl group] structure while this polymer is inferior in the acid resistance due to the presence of the binding site between the aromatic ring and the Si atom. On the other hand, polymers having no [aromatic ring—Si atom—vinyl group] structure on its terminal (for example, a polymer having an [aromatic ring—alkylene group—vinyl group] structure on its terminal or a polymer having an [amide group having an aromatic ring substituent in the side chain—alkylene group—vinyl group] structure on its terminal) have excellent acid resistance while these polymers suffered from inferior rapid curability.